2.3 Determination of plant growth indicators
One V. natans plant was randomly selected from each column at
each sampling time, and after being cleaned, their growth indicators
were determined including height, plant biomass, leaf number, and root
length. The chlorophyll content and malondialdehyde (MDA) content of
leaves were determined by the Lichtenthaler - Arnon method and
thiobarbituric acid method, respectively. The superoxide dismutase (SOD)
and catalase (CAT) activity were determined by guaiacol method, and root
activity was determined by triphenyl tetrazo - lium chloride (TTC)
method (Yang et al. 2012).